1. Field of the Invention
This invention relates to a method of detecting a floated lead of an electrical component and, more particularly, to means for detecting a floated lead of an electrical component by radiating a laser light from a laser device toward the leads of the electrical component, calculating a virtual plane including the leads, and obtaining a height difference of the leads with respect to the virtual plane.
2. Description of the Prior Art
When a lead is floated in a case where an electrical component having a plurality of leads such as a QFP is placed on a substrate, the lead cannot be bonded to the electrode of the substrate. For this reason, heretofore, as shown in FIG. 5, there has been known means for radiating a laser light from a laser device 103 toward the leads 102 of an electrical component 101 sucked to a nozzle 100 and obtaining heights Z1, Z2,.. of the leads 102 from a reference surface S to detect the float of the lead 102.
There are as causes of the floating of the lead of an electrical component, in addition to bending, deforming of a lead, an inclination error .DELTA..theta.1 of axial center of a nozzle, an inclination error .DELTA..theta.2 of the lower surface of a nozzle for sucking an electrical component, an inclination error of the upper surface of a mold of an electrical component, a positional error of a XY table for moving a pick and place head in X-Y directions, etc. If there is such a mechanical error or a constant error, the electrical component 101 is inclined just .DELTA..theta. with respect to a horizontal plane L to cause an error .DELTA.Z therebetween. Therefore, there is a problem of erroneously judging the floating of the lead 102.